Filter



Sept- 22, 1942. w. NEUMANN 2,296,566

ATTORNEYS.

lJNTE J FILTER `Willy Neumann,

Ladeburg', near Bernau, Germany; vested in the Aiien Property Custodian application August z, iesa'senal No. 287,97@

l In Germany August l0, i938 4 Claims. (Si. 1253-110) The present invention relates to a nue illter comprising plates wetted with viscous material whereby air or gas is freed from even the finest solid or liquid impurities entrained thereby.`

By the invention there is solved the problem of providing with simple means a filter having a high iiltering capacity and a large storage capacity i'or separated impurities, and offering little resistance to flow of the air or rgas to be Furthermore, the invention provides a con- .struction of filter which is relatively light in weight and which can be readily cleaned without requiring to be taken apart. g

The invention is based on the observation that the filtering power of open-work or foraminous or apertured plates is increased to an unexpect ed extent when these plates, which arepacked together in the usual manner, are not .traversed perpendicularly to the plane thereof by the gas caused to iiow over the surface `oi said plates; thatis, when the iilter is arranged with the plates disposed edgewise to the direction of iiow of the With this arrangement the result isv air or gas. also obtained that with the same depth of package the resistance to flow is considerably less than when the air or gas stream impinges perpendicularly on the plates. In this connection it may he remarked that the area of the aperturein the oraminous or open-work plate is of subordinate importance as regards the filtering capacity, for even .if the apertures are larger by a hundred fold or more than the particles to be retained, the extent of separation ofthe nest particles is not reduced. It is recommended. however, Athat the apertures should be bounded by sharp edges rather than by rounded edges.

It is known to construct a iilter from a pack oi solid plates in which the medium to be purified flows' through ribbon-like interstices between plates provided with projections. f In the present filter, there are Vno such symmetrical interspaces confined by iixed boundaries and extending ribbon-wise between adjoining plates. The medium to be iiltered is distributed vertically and breadthwise, each ine jet or sheet seeking the path of least resistance through the lter. The air or gas iets are repeatedly intermingled whereby there are effected alterations inl direction of flow and repeated sub-division of the stream under now. The path of ilow is not conned to a or airto be freed from impuritiesy but the gas is of the provision of apertures in the sieve-like or open-work plates, While on account of the depth of the pack of plates there is provided a large effective storage space for impurities removed from the medium to be filtered.

Even although it was previously known that iilters may be readily penetrable by light and yet have a high ltering capacity, nevertheless it was not to be expected that it would be found that in filtersv according to the invention which are highly penetrable by light lthere should be required so small a quantity oi iilter mass per unit area distributed over the iilter structure..

The invention thus contemplates the use vnii sieve-like members used as lters and disposed edgewise to the air or gasstream. v

' The invention is illustrated by way of example in the accompanying drawings in which similar Fig. l is a section through a lter' composed of apertured plates.

Fig. 2 is a section on the line 2 2 otFig. l

, showing the direction of new as indicated byl arrows.

Fig. 3 is a sectional view showing a rolled up filter band.

Figs. i through 'l are side elevational views of filter plates having a plurality oi openings formed therein, which openings are reduced in size and increased in number in the direction of flow'.

In Figs. i, 2, and fi to 7, inclusive,the iilter comprises spaced apertured plates'a wetted with a viscous material such as oil or the like. The iilter frame is designated b. The arrows indicate the direction of ow of the air to be purified in its passage through the nlter.

In the practical application ofthe invention there is realised the further advantage that, as is tute spacing members for the pack of plates, it

straight-through passage between adjoining` plates but there is oflered to the medium under having been found that such projections are` of a size suitable t0 constitute spacing members for the purpose of iine purification.

Filters according to the invention may be simply made of perforated or open-mesh structure in strips or. bands a of a width of several centimeters, and these bands may be coiled into rolls which are disposed edgewise to the stream of the Y plates arranged as shown in Fig. 1.'

Fine filters according to the invention are, as a rule, produced from metals selected inv accord- .4 ance withv the conditions. The metal surfaces are coated with viscous substance such as oil or the like. It is frequently advantageous to combine sieves or open-work plates to form a pack with perforations of varying area in each plate or varying from plate to plate. For example, as shown in Figs. 4 to 'I inclusive, there may be employed perforated or other open-work plates lthe size of the apertures of which diminishes in a direction towards the outlet from the filter. The medium then flows rst past the larger apertures; the more deeply the medium penetrates the lter, the smaller are the apertures encountered.

Finally, it is possible to replace some plates of the pack by filter cloths, so that within the pack the air also flows over the surface of filter cloths. the plates; they may, however, be much narrower, so that they bear on the plates only in the vicinity of the outlet zone for the air which is already toa large extent puried by passing over the remainder of the filter.

In all cases there is realised a ne' filter with high powers of purification whichbis impacted by theY stream in a different manner from that followed in other constructions.

From the point of view of structure it will be recognised that the improved filter has considerably greater rigidity of form than known sieve lters, as the planes of the plates are disposed in the direction of flow.

There are also realised the following important advantages:

(a) As the pressure of the air or gas under flow on the sieve or open-work metal walls falls away, these elements may be made thinner and weaker,

.or with uniform cross-section may be of larger area, because the mechanical stresses do not needto be taken into account. That is, within the same space a large number lof sieves or expanded `metal sheets may be tted; this means a correspondingly larger effective4 surface.

(b) With the arrangement according to the invention there are obtained as many small air These cloths may be of the same area as eddies as there are present meshes or apertures in the respective filter elements.- These eddies are particularly eiective if the apertures are bounded by sharp edges.

(c) As will be immediately understood, the small eddies which are formed are oppositely'directed, whereby the separation of very iine dust is promoted. This phenomenon is especially pronounced if the lter is traversed by air or gas at a higher speed than usual.

The aforesaid advantages are realised in a very simple manner with quite inexpensive means.

What is claimed is:

1. A gas lter embodying a plurality of spaced laminations extending longitudinally in straight lines parallel to each other andl to the direction of flow of the stream of gas to be filtered, each of said laminations being formed from an apertured platevhaving a viscous coating, said laminations being spaced apart to define straight unrestricted paths for the gas to be filtered and the apertures in said plates producing eddies to eiect impingement of particles carried in the gas against the plates.

2. A lter embodying a plurality of plates spaced apart to dene straight unrestricted paths therebetween, said plates being parallel to each other and to the direction of flow of the stream of gas to be ltered and said plates having apertures formed therein the number of which `increases in the direction of flow of the stream of gas, said apertures producing eddies to eiect impingement of particlesI carried by the gas against the plates. y y

3. A gas filter embodying a roll of apertured sheet metal,`the convolutions of said roll forming spaced filter laminations and having a viscous coating, said roll being arranged with its axis parallel to the direction of ow of the stream of gas to be filtered with the laminations defining straight unrestricted paths therebetween, the apertures in said sheet metal producing eddies to effect impingement of particles carried by the gas against the surfaces of the convolutions of the roll.

4. A filter embodying a plurality of plates l spaced apart to deiinestraight unrestricted paths therebetween, said plates being parallel to each other and to the direction of flow of thestream of gas to be ltered'and said plates having apertures formed -therein the edges of which are sharp, said apertures producing eddies to eflect impingement of -particles carried by the gas against the plates.

WILLY NEUMANN. 

